Conventionally, there is a vehicle seat having a mechanism that is capable of instantaneously moving a headrest forwardly so as to support a head of a sitting person when a vehicle back-side collision happens. An operation mechanism for moving the headrest forwardly is known. In the operation mechanism, an operation cable is pulled by a seat back loading that is produced by the sitting person when the vehicle back-side collision happens, so that the headrest is moved. This operation cable is disposed so as to extend from inside of the headrest to inside of the seat back through a stay that may function as a support pillar thereof. Therefore, in a case that the headrest is constructed to be detachable with respect to the seat back, it is necessary to take various structural measures in order to dispose the operation cable. For example, the operation cable is divided to two portions. The divided portions are respectively previously disposed in the headrest and the seat back, so that end portions thereof can be connected to each other when the headrest is attached to the seat back.
Japanese Laid-Open Patent Publication No. 2003-299549 teaches a technique in which electrical cables separately disposed within a headrest and a seat back can be connected to each other during headrest attaching operation. According to this technique, one of the electrical cables is inserted into a tubular stay of the headrest. A connection terminal of the cable is retained at a lower end of the stay. Conversely, the other of the electrical cables is also inserted into a cylindrical stay-insertion support that is disposed in an upper portion of the seat back. A connection terminal of the cable is retained within the cylindrical support while it is maintained in a standby condition for connection.
The connection terminals of both of the electrical cables can be coupled and axially integrally connected to each other when the stay is inserted into the cylindrical support. When the stay is operated in an insertion direction from a position in which the electrical cables are connected, an operational force is produced to cancel a condition in which the connection terminal of the electrical cable is retained in the cylindrical stay-insertion support. Thus, in a condition in which the electrical cables are connected, the stay can be inserted into a desired position in which the stay is stopped.
However, in the conventional technique described above, connection end portions of the electrical cables are moved to be axially overlapped, thereby forming a connecting structure in which claws formed in the connection end portions elastically engage with each other. Therefore, a connecting condition of the electrical cables can be released by inserting the stay into the support or pulling the stay from the support.
Thus, there is a need in the art to securely connect connection end portion of two cables by axially overlapping the connection end portions so as to be prevented from being disengaged.